The dual epidemics of HIV and TB continue unabated in many urban areas in resource-limited settings, with TB the leading cause of death among patients enrolled in antiretroviral therapy programs in South Africa. Despite substantial investment in healthcare facility-based diagnosis and treatment of TB, only a fraction of HIV-infected people in South Africa are screened for TB and complete TB treatment; therefore TB control at the community level remains poor. Efforts are urgently needed to implement and evaluate strategies that integrate early HIV and TB diagnosis, TB treatment initiation and retention in care, and to consider such strategies in the context of constrained healthcare resources. Xpert MTB/RIF, a novel, rapid, automated molecular diagnostic tool, currently deployed within centralized provincial hospitals in South Africa, has great potential for intensifid case finding at the community level among people who are not currently accessing hospital-based services. This proposal builds upon a successful mobile HIV screening unit that travels to community venues such as taxi stands and malls in the townships of Durban, South Africa. We will leverage this unique program to formally evaluate the value of using Xpert on the mobile unit, and build upon that strategy by implementing and evaluating a Test & Treat TB (T&T TB) intervention for promoting linkage to and retention in TB care. T&T TB is a package of interventions that includes: i) Xpert screening with rapid receipt of Xpert MTB/RIF test results at the mobile unit; ii) expedited TB treatment initiation with a starter pack at the mobile unit; an iii) monthly SMS (text message) appointment reminders. In a 3-arm design, we will compare: 1) T&T TB; 2) Expedited testing (Xpert screening on the mobile unit with clinic-based follow-up) or 3) Usual care (referral to clinic for TB screening). We propose a proof-of-concept randomized trial to accomplish two specific aims. The first aim is to establish the feasibility, yield, and clnical impact of a Test & Treat TB strategy on a mobile HIV screening unit in South Africa. The second aim is to assess the cost and cost-effectiveness of this integrated HIV/TB screening strategy for maximizing linkage to TB care and treatment completion. We hypothesize that the T&T TB strategy will improve rates of TB treatment completion and will be very cost-effective. The cost-effectiveness analysis offers the flexibility to examine the feasibility and affordabilityof Xpert in settings with different HIV and TB prevalences. This proposal is motivated by the 2013 Trans-NIH HIV research plan to investigate new approaches to HIV/TB integration that promote early detection and effective engagement in care, and to assess the effects of these interventions on survival, quality of care, and cost-effectiveness. This novel, mobile, rapid HIV and TB screening intervention will bring Xpert MTB/RIF technology to the point of care, at the community level, and will use innovative techniques to improve rates of TB treatment completion. This work will inform physicians, governments, and policy makers on how to maximize the benefits of community screening through timely and integrated mobile HIV/TB diagnosis and linkage to care.